The tectorial membrane (TM) is a collageneous tissue membrane overlying the organ of Corti in the mammalian cochlea. It is believed that the TM plays a central role in the active mechanism collectively known as the Cochlear Amplifier. Its role is most likely that of a mechanical filter and, therefore, knowledge of its mechanical properties is necessary for understanding its role in health and disease. Here we dissect fresh TM's from guinea pigs and mice and develop the protocol for attaching these membranes to rigid substrates. The atomic force microscope is used to collect force-distance data and we use them to extract elastic moduli and possibly anisotropy characteristics for the membrane material. These data will be used to develop realistic mechanical models of the membrane in-situ, which will then be integrated into whole cochlea models to investigate its filter characteristics. Both normal and genetically altered animals modeling various auditory deficiencies are being studied.